WHAT’S UP DOC? Photo clue to eye disease

Tuesday

Dec 5, 2017 at 10:55 AMDec 6, 2017 at 6:17 PM

By Dr. Jeff Hersh/Daily News Correspondent

Q: I heard a baby was diagnosed with cancer in her eye just from a photo on Facebook. Is this real?

A: Light enters the eye through the cornea, the clear part of the eye in front of the pupil (the black part of the eye which has muscles that allow it to enlarge to let more light in or shrink in bright conditions) and iris (the colored part of the eye), is then focused by the lens, travels through the vitreous humor (a clear gel-like substance which fills the eye and maintains its shape), then lands on the light-sensitive retina (the “screen” in the back of the eye). The retina contains the photoreceptors (rods and cones) that create electrical signals that travel through the optic nerve to the brain. These electrical signals are interpreted by the brain as our sense of vision.

Light can reflect from the retina, especially when bright light shines directly into the eye when the pupils are dilated (such as can occur when a flash photo is taken). The retina has a robust blood supply (it is well vascularized). The reflection from the highly vascularized retina can look red in a picture (the hemoglobin in blood gives it a reddish color), often called ‘red eye.’

Evaluation of a "red reflex" (done by shining a light in the baby’s eyes to visualize the red reflection from the retina) is recommended by the American Academy of Pediatrics as part of a well-baby exam. Leukocoria is the term used to describe an abnormal white pupillary reflex.

There are many possible causes of leukocoria:

The most common is a congenital cataract (about two thirds of cases of leukocoria in newborns), a clouding of the lens present at birth. This may be an inherited genetic problem (the most common cause), or may be due to an infection, medical condition (such as diabetes), inflammatory condition, reactions to certain medications, and/or other causes.Persistent fetal vasculature is when the hyaloid artery (a special blood supply to the fetus’ eye) fails to regress as the lens begins to form during the 10th week of gestation.Coats disease is when the blood-retina barrier breaks down and blood leaks into the retina.Retinoblastoma is discussed in more detail below.Other causes.

Retinoblastoma is a cancer that starts in the cells of the retina. It is an inherited condition in about 20 percent of cases, but it is most often due to a spontaneous mutation of both alleles of the retinoblastoma gene (RB1) on the long arm of chromosome 13, so it can occur in any child. Retinoblastoma accounts for over 10 percent of all cancers diagnosed during the first year of life, affecting about one per 15,000 infants. Most cases of retinoblastoma are diagnosed prior to age 18 months, with over 90 percent diagnosed by age 5.

Retinoblastoma usually affects only one eye, but in up to a third of patients it may be bilateral, and even more uncommonly it may be ‘trilateral retinoblastoma’ where there is also a primitive neuroectodermal tumor (PNET, a highly malignant tumor that may affect soft tissue and/or bone).

Retinoblastoma is suspected when leukocoria is identified (usually on a well-baby exam, but it could be noted due to asymmetric ‘red eyes’ in a photograph, or one of the baby’s caregivers may observe a whiteness in the infant’s eye). A thorough examination by a pediatric ophthalmologist can rule out other causes of leukocoria. Although it is very uncommon, a baby with strabismus (sometimes called lazy eye or ‘cross eyed’) who has been referred to an ophthalmologist may be found to have retinoblastoma. A CT scan, eye ultrasound, and/or MRI may be done to further evaluate the patient and identify the size of their tumor and the extent of their disease

Retinoblastoma is staged as:

Group A: small tumor only in the retina, not near other important structures such as the optic disk (where the optic nerve enters the eye) or the fovea (the area where there is the highest density of cones, and hence the highest visual acuity), and with no other spread within the eye.Group B: similar to group A but with the tumor close to important areas of the retina.Group C: small, well defined tumor that has small areas of spread to other parts of the eye.Group D: large or ill-defined tumor that has spread to other structures within the eye.Group E: very large tumor extending to the front of the eye, or with other features making salvage of the eye impossible.Metastatic retinoblastoma is thankfully rare on initial diagnosis.

The goal of treatment is to eradicate the cancer while preserving vision as much as possible. In addition, minimizing any complications (immediate and long term) of the treatment is very important. Retinoblastoma patients should be followed by a team of specialists, including a pediatric ophthalmologist and pediatric oncologist.

Low risk (groups A and B) may be treated by "focal techniques" to destroy the cancer, such as cryotherapy or laser photocoagulation. Medium and high-risk retinoblastomas (group C and D) are treated with chemotherapy (preferably administered through the ophthalmic artery, although in some cases intravenous chemotherapy is needed) in order to salvage the globe. The higher risk retinoblastomas (group E) are treated with complete removal of the eye, and often with adjuvant chemotherapy and radiation therapy. Metastatic retinoblastoma is treated with surgery, aggressive chemotherapy and radiation therapy, and then an autologous hematopoietic stem cell replacement.

The overall long-term survival of patients with retinoblastoma is 85 percent, better for lower stage disease and not quite this good for higher stage disease. Identifying retinoblastoma early is yet another reason why primary care, including those well-baby checks, is so important!